Republican presidential nominee Donald Trump has insisted that his campaign is united despite reports of deep divisions in the party after he made series of missteps.

Speaking at a rally in Florida, Mr Trump said the campaign was “doing really well”.

US media outlets said it was in turmoil after Mr Trump repeatedly attacked parents of a fallen US soldier.

Staffers told CNN that they “feel like they are wasting their time”.

“I just want to tell you the campaign is doing really well,” the nominee said in Daytona Beach.

“It’s never been so well united… I would say right now it’s the best in terms of being united that it’s been since we began.”

Earlier Mr Trump’s campaign chairman Paul Manafort blamed reports of disunity on Mr Trump’s opponent, Democrat Hillary Clinton.

“This is another Clinton narrative that she put out there and the media is picking up on,” he said. “Mr Trump has appeared this week at crowds that are overflowing into the street.”

The Donald Trump rollercoaster is picking up speed.

Thanks to a week with enough controversies for an entire election season, Republicans are flooding the media with reports of campaign chaos and an impending mass defection from their nominee if things don’t turn around quickly.

Behind all these stories of political discord, however, is the simple fact that while insider establishment operatives may be looking for the exits, Republican officeholders who must eventually answer to the 13 million Trump primary voters have yet to break ranks.

Things will have to get very bad – much worse than they are now – to result in the sort of doomsday scenarios currently being pondered.

It is a simple political calculus. The key, as always, is in the polls and public sentiment.

If Mr Trump appears to have a reasonable chance to win in November, he will persevere, as he has all year.

If his poll numbers crash, and Republican politicians start worrying more about losing their own races in November than alienating their party’s base, the Trump-coaster could career off the rails at last.

Going against Mr Trump is still a risky bet. And when it comes to preserving their jobs, politicians are all about minimising risk.

The New York billionaire has been sharply criticised for his attacks on the bereaved parents of a US Muslim soldier killed in Iraq.

His ongoing war of words with Khizr and Ghazala Khan – the parents of Capt Humayun Khan – has intensified rifts within the Republican Party.

NBC News reported that senior Republicans plan to stage an “intervention” to get the campaign back on message, stressing issues such as jobs and trade deals.

The effort will be led, according to NBC, by Republican National Committee Chairman Reince Priebus and Trump allies former House Speaker Newt Gingrich and former New York Mayor Rudy Giuliani.

“I think some of what Trump has done is very self-destructive,” Mr Gingrich told Fox Business Network on Wednesday.

Three prominent Republicans – including New York Congressman Richard Hanna – have said this week that they would vote for Mrs Clinton, saying Mr Trump was unfit to serve as president.

Many Republicans opposed to Mr Trump have stopped short of supporting Mrs Clinton, saying they would vote for a third candidate instead.